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Remove / Replace Oil Jets How To (fs)

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Rebuilding an FS series engine (also may apply to BP / FE) ... you may need to remove and reseat the oil jets if you are boring and honing. The oil jets must be destroyed in order to remove them so you will need to purchase some more (Cost around $30AU [$25US] each).


- Drill a 7mm hole in the centre of the oil jet

- Remove the spring & ball through the hole

- Tap the hole with an M8 x 1.25 tap to 8mm depth

- Screw a M8 x 1.25 bolt into the tapped hole

- Attach a sliding hammer to the bolt

- Pull the sliding hammer striahgt upward and discard the used oil jets.


- Temporarily install the crankshaft, connecting rod, and piston into the cleaned cylinder block.

- Coat the new oil jet (Part FS0110580A) into the hole and algin the nozzle with the pistons notch.

- Fit the oil jet into the hole and re-align the nozzle with the pistons notch.

- Put the cylinder block on the press stand.

- Verify that the new oil jet nozzle is properly aligned.

- Press fit the new oil jet into the block to a depth of 10.5-11.0mm using a pressure of 726psi minimum


- When removing the oil jet, be sure that you are pulling straight up - do not attempt to twist the jet or damage to block may result

- Alignment is critical - if it is not aligned properly it can damage the oil jet, cylinder block and the piston.

- Depth over specification can damage the oil jet nozzle. Pressure below specification indicates loose fit. If that occurs, replace the cylinder block and oil jet.

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Digging up an old thread here to add some more details.


I am pulling the oil jets from my race motor so I can block them off.  This will significantly improve oil pressure.  The jets aren't really needed with the Wiseco forged pistons that I am running.


Removing the jets requires complete disassembling the motor.  You have to remove the crank shaft so you can access them.


Once you have the motor apart, drill out the jet(s) with a 17/64" bit.  There is a little ball valve in the bottom of the jet.  Your bit will stop cutting once you drill down to the ball.  Leave the ball there while you tap the jet and thread the bolt.  This will reduce the amount of metal shavings the drop down into your block.  Use a M8x1.25 tap like mentioned above.  Spin the tap until it bottoms into the ball.  Then thread a ~1" M8x1.25 bolt into it.  It will bottom as well, leaving room to fit the slide hammer attachment under the bolt head.


I purchased this slide hammer kit from Harbor Freight.




The kit includes a tip that will slide under a bolt head.  I had to file the tip a little so it would fit over M8 bolt.


Here's the hammer with the attachment and a jet I just pulled still in place.




Here's the block with the jet pulled out of the #2 cylinder and the #1 cylinder jet still in place.



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Just literally finished complete disassembly of my sons 2001 626 FS engine and pulled the crank to find these strange oil jets, now I know how to take them out, thanks a million. But really MAZDA...really? I hate fining out I have another 120$ bill for nothing other than Mazda's inept design.

Has any one tapped that jet hole and tired to build their own nozzle? I'm giving it some thought. There's 170K on my sons car, a leak down test showed tons of air going from cylinder to cylinder and upon removing the heads it was clear the gasket was ... not gasketing... for lack of a better word like sealing! I still heard a lot of noise in the oil pan so thought perhaps rings may be bad but I think air may have just gotten in the oil gallies thru head gasket and down to the oil pan that way. But I've pulled it all apart figuring...why not, I love rebuilding and why not replace piston rings , check the cylinders and have them honed and bored if needed and pop in new rings and bearings. Basically a brand new engine. Then I see this jet nozzle. IS it possible to hone the cylinders without removing these? If the cylinders measure very well within spec and I can get my son another 150K minimum then I wont have it bored, if not its getting bored but thats 130$ penalty for these nozzles as much as the bore. 


As a bonus I've been measure every bolt for width, pitch , lenght and will post that to the group, can count the times in this group or any other auto group I've seen or asked my self about what size a bolt was. Well if any ncool workaround for this jet nozzle please advise. Thanks..............D

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